In this chapter we look at some additional aspects of sensors and actuators, aspects that could not have been discussed in conjunction with the principles of conventional devices. First, we discuss a class of devices called microelectromechanical systems (MEMS). The term MEMS relates more to the method of production of sensors and actuators, whereas the sensors and actuators themselves are some of the devices discussed previously as well as others. We discuss them here because they are unique not only in the methods used to produce them, but at least some of them can only be produced as MEMS. One can imagine an electrostatic actuator, at least in principle. But only as an MEMS device does it become a useful, practical device. Then there is the issue of scale of fabrication. Using techniques borrowed from semiconductor production, enhanced by micromachining techniques, it became possible to mass produce sensors such as accelerometers and pressure sensors, and actuators such as microvalves and pumps. Many of these devices have been developed for the automotive industry, but they have found their way into others areas, including medicine.
Chapter Contents:
- 10.1 Introduction
- 10.2 Production of MEMS
- 10.3 MEMS Sensors and Actuators
- 10.3.1 MEMS Sensors
- 10.3.1.1 Pressure Sensors
- 10.3.1.2 Mass Air Flow Sensors
- 10.3.1.3 Inertial Sensors
- 10.3.1.4 Angular Rate Sensors
- 10.3.2 MEMS Actuators
- 10.3.2.1 Thermal and Piezoelectric Actuation
- 10.3.2.2 Electrostatic Actuation
- 10.3.3 Some Applications
- 10.3.3.1 Optical Switches
- 10.3.3.2 Mirrors and Mirror Arrays
- 10.3.3.3 Pumps
- 10.3.3.4 Valves
- 10.3.3.5 Others
- 10.4 Smart Sensors and Actuators
- 10.4.1 Wireless Sensors and Actuators and Issues Associated with Their Use
- 10.4.1.1 The ISM and SRD Bands
- 10.4.1.2 The Wireless Link and Data Handling
- 10.4.1.3 Transmitters, Receivers, and Transceivers
- 10.4.2 Modulation and Demodulation
- 10.4.2.1 Amplitude Modulation
- 10.4.2.2 Frequency Modulation
- 10.4.2.3 Phase Modulation
- 10.4.2.4 Amplitude Shift Keying
- 10.4.2.5 Frequency Shift Keying
- 10.4.2.6 Phase Shift Keying
- 10.4.3 Demodulation
- 10.4.3.1 Amplitude Demodulation
- 10.4.3.2 Frequency and Phase Demodulation
- 10.4.4 Encoding and Decoding
- 10.4.4.1 Unipolar and Bipolar Encoding
- 10.4.4.2 Biphase Encoding
- 10.4.4.3 Manchester Code
- 10.5 Sensor Networks
- 10.6 Problems
Inspec keywords:
electrostatic actuators;
microsensors;
micromachining
Other keywords:
microelectromechanical system;
MEMS device;
pressure sensor;
semiconductor production;
microfabrication;
electrostatic actuator;
micromachining technique;
accelerometer;
automotive industry;
pump;
microvalve;
smart sensor
Subjects:
Electrostatic devices;
Fabrication of MEMS and NEMS devices;
Microsensors and nanosensors;
Sensing and detecting devices;
Micromechanical and nanomechanical devices and systems
